Heater 1 not working - Duet 0.85 new installation

I am trying to commission a Duet 0.85 on a Wanhao I3 . The bed heats up fine however I can't get the Extruder Heater to heat up. I suspect I have a config problem rather than a hardware problem.

The temperature readings in Pronterface are showing T:B21.9 which reading thorough posts on here is showing an error code for the Extruder heater. I have checked the resistance of the thermistor and cold it is showing 180k ohms.
My config file is for the tool 0 as follows

Thanks, I'll put the T0 into the config.
My intention is to use the web interface, but I print in a garage and my WiFi signal is weak. I haven't got a network cable in there yet. I am looking to use a WiFi extender, but I'm keen to get my 3d printer back up and running again. Anyway the advice dc42 gave me has fixed the heater problem. So time to get steppers working now.
Thanks again